Pls help me on the following problem to work out for (b).

Research workers measured the body lengths, in mm, of 10 specimens of fish spawn of a certain species off the coast of eastern Scotland and found these lengths to be 12.5, 10.2, 11.1, 9.6, 12.1, 9.3, 10.7, 11.4, 14.7, 10.4.
(a) Obtain unbiased estimates for the mean and variance of the lengths of all such fish spawn off eastern Scotland.
(b)Research shows that for a very large number of specimens of spawn of this species off the coast of Wales the mean body length is 10.2 mm. Assuming that the variance of the lengths of Spawn off eastern Scotlnand is 2.56, perform a significance test at the 5% level to decide whether or not the mean body length of fish spawn off the coast of eastern Scotland is larger than that of fish spawn off the coast of Wales.